Plaster cast cutting shears



July 8, 1952 cK 2,692,224

PLASTER CAST CUTTING SHEAR-S Filed Aug. 28, 1950 Patented July 8, 1952 UNITED STTS The present invention relatesto improvement in plaster cast cutting shears and more particularly to a device as set forth operated by hydraulic means.

Broadly, the invention comprises a pair of cutting jaws, much like the ones used manually, one of said jaws being stationary and a further jaw provided with an inverted T-shaped heel adapted to be disposed adjacent the flesh beneath the plaster cast, and operated by hydraulic means manually controlled by means of a valve which is constructed to direct the pressure means either to open, close the jaws or maintain the jaws motionless.

The main objects of the invention are therefore the provisions of a hydraulically operated plaster cast cutting shears which is extremely 1 Claim. (Cl. 30-228) simple in construction, easy to operate, efficient,

strong and durable and of comparatively low manufacturing cost.

It is to be understood, that while the preferred embodiment of the controlling valve is shown in the accompanying drawing, a sleeve valve between the plunger and cylinder could be used as well as the one shown thereon, and could be made to operate automatically by holding an ordinary valve open with the thumb in the position ofthe two-way valve shown on the accompanying drawing.

It is therefore another object of the present invention to provide a device formed with a manually or an automatically operated valve.

With these and other objects in view that may appear as the description proceeds, the invention consists in the novelarrangement of cooperating elements, as hereinafter more specifically set forth, claimed and shown in the accompanying drawing forming part of this application, and in which:

Figure 1 illustrates a sectional elevational view of a plaster cast cutting shear constructed in accordance with my invention, and

Figure 2 illustrates a sectional view of the manually operated valve.

Referring more in detail to the drawing in which similar reference characters designate corresponding parts throughout the two views, it will be seen the invention comprises a cutting shear having a stationary jaw 5 provided with a cutting edge 6 and an extension I on which is mounted a carrying handle 8. A second handle 9 is disposed transversely to the extension 1 and is secured thereto at the jaw extremity.

On the carrying handle 8, at the inner extremity thereof is fastened a U-shaped bracket ID on which is pivotally secured a cylinder H by means of which the mobile jaw I2 is operated. The said mobile jaw is provided with an inverted T-shaped heel I3 which is adapted to bear against the skin inside the cast during the cutting operation.

Within the cylinder H is apiston I4 having a piston rod l5 at the outer end of which is secured a rectangular block [6 and on which is v pivotally connected 'a link ll by means of which the mobile jaw I2 is operated. The said link is further pivotally connected at It on the stationary jaw. V

The device is operated by fluid under pressure supplied by a conventional compressor not shown in the drawing. I

The operation of the device is as follows:

Oil or any other suitable fluid is forced into tube I! by means of the aforementioned compressor, and through valve 29 and into the cylinder 2|, forcing the plunger l4 forward, opening the jaws and at the same time forcing the fluid in the cylinder at I! through the return tube 22 back through the valve and out through tube 23 to the compressor. The reverse action of the plunger to close the jaws is executed by pressing the lever 24 which operates the valve in the position 25 as shown by dotted lines on Figure 2 of the drawing. When the valve is arranged to block the entrance of tube l9 and the exit tube 23, the jaws are motionless.

While the preferred embodiment has been disclosed it is understood that minor detail differences may be resorted to without departing from the spirit of the invention.

I claim:

A plaster cast cutting shear comprising a stationary jaw, an extension on said jaw, a handle carried by said extension, a cylinder carried by said handle, a pivotal connection between one end of said cylinder and said handle, a piston movable in said cylinder, a piston rod connected to said'piston and extending out of said cylinder, a link pivotally connected at one end to said piston rod, a pivotal connection between the other end of said link and said fixed jaw, amovable jaw, a pivotal connection between said link and said movable jaw spaced from'the pivotal connection between said link and said fixed jaw, and

means for selectively introducing fluid into said cylinder on either side of said piston to move said piston and hence said link alternatively to open and close said jaw.

NEIL MCKAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 1,868,922 Schwerin July 26, 1932 

